602 results about "Double pulse" patented technology

The invention relates to the technical field of production manufacturing of a cast middle groove by a heavy-duty scraper conveyor used on coal mines, and provides a robot automatic welding production line of a middle groove and a technological method thereof. The production line designs 8 stations according to the manufacturing process flow of the middle groove, comprises 6 parts of a primary assembly station, a middle plate preheating station, a backing welding station, a middle plate and bottom plate robot welding work station, a secondary assembly station and a bending rail rest robot welding work station, and forms an integrated production line layout of the middle groove. The invention integrates and uses multiple technologies of a welding robot, double-wire welding, digital double-pulse welding power source, computer control, high-efficiency flame preheating and the like, and establishes technical measures of preheating temperature, bevel form, welding sequence, welding parameters and the like; and the welding process is controlled by a computer, thereby realizing high-efficiency automatic robot welding of the middle groove in the overall process. Compared with the traditional manual gas shielded welding, the invention obviously improves the welding quality of the middle groove and increases the welding efficiency by 3-4 times.

The present invention relates to a current transformer IGBT power module field double-pulse testing system and a method. The testing system comprises a double-pulse testing circuit which comprises a double-pulse testing circuit which comprises an input power supply (1), a current transformer and a load which are connected in order, a detection unit which is used for detecting the relevant parameters of each IGBT in the IGBT power module (3) in the current transformer, a data acquisition unit which is connected to the detection unit and is used for collecting the measured relevant parameters of the IGBT, and a data processing unit which is connected to the data acquisition unit and is used for carrying out analyzing processing on the measured relevant parameters of the IGBT. The testing method comprises the steps of (1) constructing a double-pulse testing circuit, (2) carrying out data measurement to measure the switch parameter of each IGBT in the IGBT power module (3) in the current transformer, and (3) carrying out data processing to carrying out analyzing processing on the measured switch parameter of the IGBT. Compared with the prior art, the system and the method have the advantages of accurate measurement and convenient measurement and are suitable for field measurement.

The invention discloses a testing device and a testing method for a three-dimensional PIV (Particle Image Velocimetry) internal flow field testing system of a hydraulic retarder. The testing device comprises a driving motor, a transmission case, a pneumatic clutch, a flywheel case, a torsion and rotating speed sensor, a braking shaft, a visualized hydraulic retarder, a visualized testing chamber, a circular guide rail, a synchronizer, a double-pulse laser, CCD (Charge Coupled Device) cameras, a water storage tank, a water pump, a pressure inductor, a pressure reducer, a particle dispenser, an electromagnetic flowmeter and the like; the visualized testing chamber is made of a transparent material and is suitable for an aqueous medium; the braking shaft is driven by an external driving system, is supported by a bearing, passes through a shell of the hydraulic retarder and is connected with a driving wheel of the retarder; the first CCD camera is arranged at the top of the visualized testing chamber and is used for shooting downwards; the second CCD camera and the double-pulse laser are arranged on the circular guide rail and can arbitrarily rotate along the guide rail; and the circular guide rail and the visualized testing chamber are respectively fixed on the base. The testing device and the method disclosed by the invention can be used for carrying out three-dimensional PIV measurement on the internal flow field of the hydraulic retarder and is simple and compact in structure, good in universality and easy to control.

A method for dynamic characterization of an electrochemical system (such as a lithium-ion battery) is provided, comprising exciting an electrochemical system with a plurality of double-pulse sequences, each comprising a constant-current discharge pulse, a constant-current charge pulse having the same pulse width and pulse amplitude, and a zero-current period between the pulses; and calculating an impulse response, using a recursive or matrix-based method, to dynamically characterize the electrochemical system. A constant state-of-charge is maintained in the electrochemical system. Therefore the signal-to-noise ratio is high due to the repetition of the driving sequence. This method may be employed for on-line determination of the impedance spectrum of an electrochemical system, since the cycling profile can be easily integrated into charge/discharge profiles. Batteries (and other devices) can be diagnosed at high speed and with high accuracy. The double-pulse sequence is robust for fairly noisy systems.

An optical transmitter which modulates the phases and intensities of double pulses and then transmits them, includes a branching section which branches each of the input double pulses to first and second paths, a first optical modulator placed in the first path, second and third optical modulators placed in series in the second path, and a combining section which combines the double pulses having traveled through the first path with the double pulses having traveled through the second path to output double pulses. A control section controls such that each of the first and second optical modulators performs any one of relative intensity modulation and relative phase modulation on the double pulses passing through, and the third optical modulator performs relative phase modulation on the double pulses passing through.

The invention belongs to the technical field of power semiconductor devices, and particularly relates to a double-pulse test method for an insulated gate bipolar transistor (IGBT) module. On and off of the tested IGBT module can be controlled by adding a driving positive voltage and a negative voltage between the grid and the emitter of the tested IGBT module; and two times of pulse width modulation (PWM) pulse are send to and blocked for the IGBT module, so that the IGBT module is subjected to an on-off-on-off process, the over current bearing capacity of the module and the capacity of mastering the on and off properties of the module are checked, and reference and basis are provided for application of the high-voltage and high-current IGBT module.

A device for testing a turbulent flow blending flow field in a crosscurrent comprises a blending test section communicated with a main airflow; an atomizing nozzle is arranged on the blending test section and communicated therewith; matt paint is uniformly applied onto the inner wall of the blending test section; a plurality of slits are formed on the lateral wall of the blending test section; a double pulse Nd:YAG laser is arranged on one side of the blending test section, and the slits are formed on the side; a CCD camera is arranged at the outlet of the blending test section; and the double pulse Nd:YAG laser and the CCD camera are connected with a computer through a PIV synchronous controller separately. The invention addresses the difficulties in filming the flow field of a rotating flow centrifugal nozzle in a limited passage during the process of atomizing blending in the cross flow, such as liquid accumulation on the inner wall, the influence of ambient light, the arrangement of the camera and frequent calibration due to the filming of different sections, and at last can obtain a clear blending particle picture, thereby obtaining the important information about the flow field, the velocity field, the distribution of vorticity and the like.

The invention discloses an on-line in situ detecting method for an infrared-ultraviolet double pulse laser induced breakdown spectroscopy, which at least comprises the following steps of: A. setting a pulse delay time according to the sample excitation characteristics to control the time interval of two lasers; B. firstly outputting laser from an infrared waveband laser, long-distance collecting, adjusting and focusing on a position to be detected, and ablating the sample to generate plasma; C. outputting laser from an ultraviolet waveband laser after a delay time, long-distance collecting, adjusting and focusing on the same position, and exciting the plasma to reinforce a spectrum signal; D. receiving the spectrum signal through a long-distance spectrum collecting device, coupling the spectrum signal in an optical fiber, transmitting the spectrum signal to a spectrograph, and obtaining the spectrum data information through an assorted software; E. collecting the spectrum data, and obtaining a detection ingredient analysis result by a calibration-free correction analysis method.

The present invention discloses a method including: writing a phase change material from a high RESET state to a weakened RESET state with a first step; writing the phase change material from the weakened RESET state to a SET state with a second step, the second step having a lower current than the first step; verifying a parameter of the phase change material wherein if the parameter is higher than a target for a SET state, then repeating the writing with the first step, the writing with the second step, and the verifying until the parameter is lower than the target wherein a current for the first step is decreased by a decrement with each iteration without becoming lower than a current for the second step.

The invention discloses a double-pulse phase sensitive OTDR (optical time-domain reflectometer) integrated with a weak reflection grating, and the OTDR comprises a narrow-pulse laser, a light modulator, a circulator, a data collection device, an avalanche detector, a weak reflection grating array, a sensing optical fiber, and a pulse signal generator. The invention also discloses a vibration measurement method for the OTDR. The OTDR employs a mode of integrating with the weak reflection grating, and improves the signal to noise ratio of a system. Through employing a double-pulse detection method, the OTDR solves a problem that most of grating sensing is just sensitive to the position event of a grating, and is enabled to be sensitive to all events of the sensing fiber along a line. Because the signal to noise ratio of the system is very high, the OTDR can measure the high-frequency vibration of limit frequency under the limiting of the length of the sensing fiber, and also can measure the low-frequency vibration (less than 10 hertz).

The invention discloses a circuit and a method for measuring stray inductance of a current conversion circuit of a three-level converter. The circuit comprises a first IGBT (insulated gate bipolar transistor), a second IGBT, a third IGBT, a fourth IBGT, a first clamp diode, a second clamp diode, a first resonant capacitor, a second resonant capacitor, a first direct-current support capacitor, a second direct-current support capacitor, a laminated busbar, a direct-current power supply and a freewheel reactor. The method includes forming different freewheel circuits by the freewheel reactor; exerting double pulses to each corresponding IGBT; taking an average value of resonance current frequencies at a turn-on moment and a turn-off moment; and precisely computing the stray inductance of the current conversion circuit by an LC parallel resonance characteristic realized by the resonant capacitors and the stray inductance of the circuit. The circuit and the method have the advantages that actual operation is facilitated, the stray inductance of the current conversion circuit of the three-level converter can be accurately measured, overvoltage levels of a power device under different current grades of the three-level converter can be accurately controlled conveniently, and accordingly establishment of a system control strategy can be guided.

The invention discloses a photoelectric double-pulse laser induced breakdown spectrograph, comprising a pulse laser, a focusing lens, a movable platform, a discharge electrode, an optical diode, a pulse time-delay controller, a high-voltage pulse power supply, an optical collection system of optical radiation, a monochromator or a spectrograph, a photoelectric conversion element, a data collection unit and an electronic computer. The invention also discloses a spectral analysis method of the photoelectric double-pulse laser induced breakdown spectrograph. The photoelectric double-pulse laser induced breakdown spectrograph can greatly enhance the spectral analysis sensitivity.

The invention discloses a motor revolving speed measurement and fault state detection system, which comprises a filtering circuit, a frequency doubling and phase discriminating circuit, a speed counter and a revolving speed calculating and fault detection module, wherein the filtering circuit is used for filtering a three-phase interference pulse signal output by a motor encoder, and the filtered signal is output to the frequency doubling and phase discriminating circuit; the frequency doubling and phase discriminating circuit is used for carrying out frequency doubling processing on an encoder pulse signal; when the encoder rotates, the rotation direction of the encoder is judged by judging a B-phase electrical level; a signal subjected to frequency doubling processing is output to the speed counter; the speed counter is used for counting high-frequency clock pulse and encoder frequency doubling pulse according to an M/T anemometry principle within set speed sampling time; the revolving speed calculating and fault detection module is used for calculating the revolving speed value of the motor; and meanwhile, the signal pulse is detected to obtain encoder fault information. The motor revolving speed measurement and fault state detection system disclosed by the invention can be suitable for a wider motor revolving speed work range, can be used for detecting the information state of motor encoder faults and is convenient for system to find faults in time and carry out necessary processing.

The invention discloses a wear-resistant workpiece and a manufacturing method of a wear-resistant coating thereof. The preparation method of the wear-resistant coating comprises the following steps: forming a preparation piece according to the structure of a required wear-resistant workpiece; coating nickel on the surface of the preparation piece through a double-pulse method, thus forming a nickel-coated transition piece; and coating a hard chromium layer on the surface of the nickel-coated transition piece, thus forming the wear-resistant coating on the surface of the preparation piece. For the manufacturing method of the wear-resistant workpiece, a step of coating nickel on the surface of the workpiece through a double-pulse nickel coating method is added; and the double-pulse nickel coating method is characterized in that the magnitude of current or voltage is regulated by an external control means, the current is additionally controlled by controlling the pulse switch-on time, the pulse switch-off time, the pulse duty factor, the pulse current density and the like, and corresponding variables are changed to respectively achieve the effects of increasing the cathode current density, inhibiting the generation of side reaction, reducing the impurity content in the coating, improving the current distribution and the like, thus improving the quality of the coated nickel layer and prolonging the service life of the wear-resistant workpiece.

The invention discloses an aluminum alloy digital welding machine with smooth transition double-pulse parameters, which comprises a power main circuit, a main control mother board, a main control micro controller unit (MCU), a wire feed driving circuit, an advanced RISC machine (ARM) controlled human-machine interactive system and a hardware proportion integration differentiation (PID) controller, wherein the hardware PID controller, the wire feed driving circuit and the main control MCU are arranged on the main control mother board; the wire feed driving circuit is connected with the main control MCU; the hardware PID controller is connected with the main control MCU and the control port of the power main circuit; the current input end of the power main circuit is connected with the utility power; and the current output end of the power main circuit is connected with a welding load. The MCU and the ARM are used as control cores, pulse width modulation (PWM) is generated through the hardware PID controller to realize driving control of the main circuit, the work load of the main control MCU is reduced, the main control MCU quickly and stably completes welding process flow control and double-pulse waveform database management task, the welding efficiency is improved, and stable welding of aluminum alloy from low current to high current is realized.

The invention relates a transient speckle measurement optical system based on a double-pulse laser, and belongs to the field of dynamic mechanical quantity laser measurement. The system comprises a light source, a light path transmission system and a photoelectric receiving system; the light source emits double-pulse laser, the energy of the laser is adjusted by an attenuation piece, and the space filtering is carried out for speckles of the laser by a space filtering mirror group which consists of a first long focal length lens, a metal pinhole and a second long focal length lens; the light beam passes through a second reflector after the space filtering is expanded and collimated by a first reflector, an expanded beam lens and a collimating lens, and is divided into a path of measurement light and a path of reference light through a beam splitter prism to be incident on a measured surface and a reference surface respectively; the two paths of scattered light are gathered after passing through the beam splitter prism, and are interfered mutually; and the interfered light beam is imaged on the receiving surface of a CCD (Charge-Coupled Device) camera by an eyepiece. The system obtains speckle images of transient vibration of an object structure surface in an adjustable time interval; and the signal to noise ratio of the obtained speckle images is high.

The invention discloses a measuring device and a measuring method for micro-channel velocity distribution, including a microscope, a double-pulse laser, a photons detector, a synchronous controller and a processor. The method includes the following steps: 1) regulating all instruments to a working state; 2) injecting fluorescent particle solution into micro channel and drive the liquid flowing in the channel; 3) adjusting the vertical position of lens to the clearest imaging position on the bottom surface of the micro channel; 4) the distance between two light spots on the same particle irradiating by the double-pulse laser should be within 20 to 50 pixels; 5) continuously shooting multi-frame images under the irradiation of the double-pulse laser; 6) adjusting the focal plane of lens to a new position and shoot multi-frame images again; 7) repeating the step 6) and shooting images in different positions. The invention has the advantages of high optical sensitivity, high spatial resolution of flow speed detection and high adjustable accuracy of vertical displacement.

The invention relates to a method for preparing dense fluoride ceramic films on a magnesium surface and a magnesium alloy surface and belongs to the technical field of metal surface treatment. The method comprises the following steps of: chemically passivating a magnesium alloy; preparing a single-pulse ceramic film; and preparing a double-pulse ceramic film. In a chemically passivating process, solution such as hydrofluoric acid, phosphoric acid, hydrogen fluoride amine and the like are used; the preparations of the single-pulse ceramic film and the double-pulse ceramic film are mainly performed in a fluoride electrolyte-containing system, wherein potassium fluoride (sodium) is taken as a main salt; phosphate is taken as an additive; and citrate or tartrate is taken as a main stabilizing agent. The fluoride ceramic film obtained by the method is complete and dense, has high hardness, is firmly combined with a substrate, can be separately used as a protective layer and can be prepared into a composite surface functional layer which has higher corrosion resistance, higher wearing resistance and high hardness after subsequent processing treatment. The overall process of the method has the advantages of simple flow, low equipment cost, environment friendliness and the like.

Provided is a method for preparing a two-dimensional metallic photonic crystal structure in large area through femtosecond laser direct writing. The invention provides a method and experiment device for preparing the periodically-distributed two-dimensional photonic crystal structure with the feature size being the sub-micron dimension in one step in the large area by focusing identical-wavelength double-pulse femtosecond laser on the surface of metal through a plano-convex cylindrical lens, and the identical-wavelength double-pulse femtosecond laser is obtained based on the spectrophotometry of birefringent crystals and has the features of collinear transmission, cross polarization and picosecond time delay. Two-dimensional periodic structure patterns can be effectively regulated and controlled by changing the energy and the number of pulses of input laser, the thicknesses and the azimuth angles of the birefringent crystals and the like. Through the combined design of different linear polarization directions and the variable time delay feature of two femtosecond laser pulses and focusing of the cylindrical lens, preparation of the two-dimensional metallic photonic crystal structure within the large area is achieved conveniently and quickly. The novel preparation method adopting the double-pulse femtosecond laser with cross polarization and variable time delay has potential important applications in the field of material micro-nano processing and preparation.